This invention relates to a digital speed controller for rotating machinery and more particularly to controllers based on the use of a single-chip microcontroller.
Velocity control of rotating machinery, such as steam and gas turbines and rotating electric machines, requires a determination of the present rate compared to a set rate. The resultant error, the speed error, drives a power controller more or less based upon the sign of the result to maintain the system at the set rate. The problem presented, for which a totally satisfactory solution has not yet been suggested, is to replace existing analog speed controls with digital logic. The purpose of doing this is to increase reliability, reduce costs, allow for distributed control and fault tolerance, and other like considerations. While voltage to frequency converters and some digital counting schemes have been implemented to perform some forms of non-critical, low resolution speed control, the use of a microcontroller unit (MCU) to achieve high control loop rates has not been proposed heretofore.